The following process is disclosed by Dahlbom, R. et al. Acta Pharm. Suec. 22, 147-156(1985).

Dahlbom et al. disclose on page 151 (paragraph 4) that “4-[n]itropyrazole (3.0 g, 0.027 mol) in ethanol (50 ml) and 5M HCl (12 ml) was hydrogenated over a palladium catalyst (5% on Al2O3) in a Parr apparatus at an initial pressure of 3-3.5 atm for 2 h. After filtration and evaporation of the solvent in vacuo, the residue was purified by column chromatography (Al2O3, CHCl3—CH3OH (9:1)), affording 2.1 g (68%) of the title compound[.]”
For purposes of clarity, 5M (mol/L) HCl (hydrochloric acid), is a concentration of about 15% by weight hydrogen chloride gas in water. Additionally, 3-3.5 atm (atmospheres), is a pressure of about 300 kilopascals (kPa) to about 350 kPa.
It is noteworthy that the process disclosed by Dahlbom et al. was performed at a volume/volume (v/v) ratio of ethanol to hydrochloric acid of about 4:1. Likewise, the Dahlbom report does not disclose the temperature at which this process is conducted, nor does it report the catalyst loading of palladium on alumina.
The following process is disclosed by Ramsden, N. et al. WO 2011/048082 A1, 115(2011).

Ramsden et al. disclose on page 115 (lines 5-9) that “[a] solution of 4-nitropyrazole (500 mg, 4.4 mmol) and palladium on alumina (50 mg) in ethanol (10 mL) and hydrochloric acid (2 mL, 6M aqueous solution) was stirred at rt under a balloon of H2 for 16 h. The mixture was then filtered through Celite and the filtrate concentrated in vacuo to give 3-chloro-1H-pyrazol-4-amine.”
For purposes of clarity, 6M hydrochloric acid, is a concentration of about 19% by weight hydrogen chloride gas in water. Additionally, a balloon of H2 (hydrogen gas), is a pressure of about 1 atmosphere, which is equivalent to a pressure of about 100 kPa.
It is noteworthy that the process disclosed by Ramsden et al. was performed at a volume/volume (v/v) ratio of ethanol to hydrochloric acid of 5:1. Likewise, the Ramsden report does not disclose the weight percentage of palladium on alumina, the type of reaction vessel used, or the yield of the reaction.